Guys, you've pointed the finger on the main issue that I asked myself when I did the wonder. The answer is "yes", I'm aware about it and it's intentional. There are several reasons for that (not necessarily in order of importance):
a) Playing as Egyptian you start with a 25% bonus
b) IIRC there is a early Tradition policy which gives a 20-25% bonus
c) If placed at the beginning, human player would have a clear advantage on AI in order to build it first - do you like win easy?
d) Although in the Renaissance era, it is on the more likely path (just after gunpowder), which means at half of game, more or less
e) Yes, I know that most of the wonders have been already built, but there are still several important wonders to reach and its effect might give a decisive help in the rush towards the kind of victory you choose for the game (cultural, scientific, UN, etc...)
f) all in all, it seems a "balanced" effect - it comes late but you may take advantage by it as well if you decide to build it
I thank you very much for the feedback - feedback gives sense to modder efforts
